With a personal computer or other kind of data processing terminal, digital images can be corrected in color-balance, tone curve or other characteristics, to improve their qualities. For example, image data taken through a digital camera are sent to the personal computer. Then, an operator may adjusts various kinds of correction parameters while observing images displayed on a monitor of the personal computer based on the image data, in order to finish images according to the operator's intension. In case of a digital camera that can output original or raw image data that is not subjected to white-balance correction or other image-processing, it is possible to correct images in the personal computer without missing any color data on the side of the digital camera.
As an efficient image correction method, Japanese Laid-open Patent Application No. Hei 11-136528 suggests displaying a number of sample images of the same content but corrected with different correction parameters, simultaneously on the monitor, to allow an operator to select one among those sample images while observing differences in correction result between the different correction parameters. Then, the image data is processed with the correction parameter corresponding to the selected sample image.
Since the above mentioned prior art displays the sample images separately from one another, the operators have to move their eyes widely and repeatedly to compare the sample images to each other, so it is difficult to differentiate between the correction results when the correction parameters are finely adjusted. But in those cases seeking high-quality images with special intentions, such as wedding shots, commercial shots and other studio shots, it is necessary to adjust the correction parameters finely and strictly.